Determining primary product ion from the mesoscale oxygen field
Net biological oxygen production can be determined from models of time-series measurements of the oxygen field, so long as there are simultaneous measurements of inert gas tracers to estimate the role of air-water transfer and mixing with the ocean interior. In the two locations where this has been done, the oxygen balance yields net nutrient production values that are within a factor of three of sediment trap and in vitro incubation experiments. Initial findings from a similar study at the US JGOFS timeseries station near Hawaii (Station ALOHA) reveal that nitrogen uptake determined by net biological O2 production in the upper 175 m, which includes both the euphotic and shallow respiration zones, agrees to within a factor of two of the mean annual sediment trap N flux at 150 m. Poorly known processes that should be explored to reconcile differences in the various methods are: (a) transport of dissolved and suspended particulate organic matter out of the euphotic zone, (b) alteration of O2:DIC:NO3 stoichiometry in the euphotic zone by production of carbon-rich dissolved organic matter, and (c) bacterial heterotrophic NO3 uptake.
Article from Marine Science Symposia Vol. 197 - "Measurement of Primary Production from the Molecular to the Global Scale". Symposium held in La Rochelle, 21-24 April 1992. To access the remaining articles please click on the keyword "MSS Vol. 197".